Extension ladder



2 5 1 6 A 1 UR m C A L L AN Wm s Hm T Gm July 17, 1923.

Filed May 6 1922 2 Sheets-Sheet l Patented July 17, 1923.

units! STATES PATENT caries.

GEORGE nwALcHLI, or s r. LOUIS, nizssounif, assronosro KANT BREAK LADDERS.

' INCL, on ST. Louis; no, a CORP'QRATION or MISSOURI.

EXTENSION LADDER.

To all whom itma z concern:

Be it: known that LGEonon H. VVALQHLI,

a citizen of the United States, residing at,

St. Louis, State of Missouri,.have invented certain. new and useful Improvements in Extension Ladders, of which the following is a specification.

My invention: relates to improvements in ladder construction and more particularly to improvements in extension ladders of the kind, that is used-in erecting, roofing. and painting.- houses, and 'the mainobject of the invention is to provide a ladderthat isv comparatively light but has at theusa-me time ample strength. for the usev for which it is intended.

For thispurpose I reinforce. not only the sides but also the rungs of my ladder.

The advantage claimed for this construction is accordingly this, that the sides are prevented from splitting, bending and breaking, as well as from spreading, and the rungs from breaking.

One embodiment of the invention is illustrated in the accompanying drawings,

where Figure 1 shows a perspective view of an extension ladder as erected against a wall;

Fig. 2 is a fragmentary side view of the same;

Fig. 3 is a longitudinal section along line 3-3 of Fig. 2;

Fig. 4: is a horizontal section along line 4- 1 of Fig. 2;

Fig. 5 is a longitudinal section along line 55 of Fig. 3, and

Fig. 6 is a perpendicular section along line 66 of Fig. 1.

The ladder consists of a pair of sides or uprights 10 preferably of wood and connected by means of a number of rungs 11 also lnade of wood. The reference numeral 12 indicates the extension part of the ladder which, in the usual manner, is intended to slide up and down the principal ladder in guides 13 and held in adjusted position by means of dogs 14. The upper ladder 12 is hoisted on the main ladder by means of a tackle and block device 15 of the usual construction.

As best seen in Figs. 3 and 6 the rungs 11 are made in two parts, that is to say, they are split along their longitudinal axis, as

at 16, and have tapered ends 17 set into the sides 10 in suitable counter-bores 18 provided for this purpose A sleeve 19 sur rounds-each rung to keep the halves thereof together and to prevent displacement there of and each rung is provided with a central bore through which a bolt 20: runs This bolt is preferably made of iron wire and threadedatone or both ends, as it 21, or it may. have ahead 22 at the other end. By means of a nut23ancl a washer 24 the bolt 20, rungs 11 and two sides 10 are held firmly together, and in order that the outer faces of the sides 10 may be without. obstructions the headsand nuts are: countersunk in the wood, as at 25.

Along the front and rear edges of the sides 10 I provide a narrow groove 26 running the entire length of the sides and: also across the top end thereof. In this groove is laid a continuous wire 27 bent in U-shape, so as to be embedded in the grooves 26 both along the edges and the top of each side 10. The lower ends of the wire 27 terminate each with a loop 28 and these two loops are positioned opposite each other in the edges of the sides, so that they may be held securely therein by means of a cross bolt 29 tightened by means of a nut 30. Bracing bolts 31 are also provided for connecting the two parallel lengths of the wire 27 and these bolts are preferably provided with a hook 131 at one end engaging one side of the wire and a bent washer 32 at the opposite end where a nut 33 draws the parts together, the bolts 31 running through the body of each side 10, as best seen in Fig. 4. In this manner the U-shaped wire 27 is securely held in the grooves provided therefor and it will be readily understood that this construction considerably strengthens the sides of the ladder, so that the latter may be lightly constructed. By means of the reinforced rungs, these will not only be strengthened against breaking or bending but the sides will be prevented from spreading when a heavy load is placed on the rungs.

It will be evident that not only extension ladders may be constructed in this manner but ordinary single ladders and step ladders may also be strengthened in the same way.

The splitting of the rungs as described above is made for simplifying the construction, but at times it might be preferable, particularly if suitable wood is available that the rungs be made in one piece and pro- I vided with a central bore for insertion of the bolts 20. When the rungs are split,"how ever, as indicated in Figs. 1, 3 and 6, the sleeves 19 are very essential for increasing the strength oi the rungs. The sleeves may be shrunk in place, or if made open, riveted or nailed around the rungs.

Having thus described the invention, what is claimed as new is:

1. In a ladder having a pair of wooden sides and wooden rungs between said sides with their ends countersunk therein, said sides being provided with grooves along their edges and across their upper ends, a

continuous wire embedded in'the grooves of each side and spaced bracing I bolts through said sides, a hook at one end of each bolt, a nut threaded on theother end thereof and a hooked washer under said nut, said hooks engaging with said wire.

'2. In a'ladder having a pair of wooden sides and'wooden rungs between said sides with their ends countersunk therein, each of said rungs being split along an axial plane and provided with a central bore, a bolt inserted in said bore, and means drawing said bolt, rung and sides'togethen'said sides! being provided with grooves along their edges and across their upper ends, a continuous wire embedded in the grooves, of each side and spaced bracing bolts through said sides provided with hooked ends engaging with the wire.

3. In a ladder having a pair of wooden sides and wooden rungs between said sides with their ends countersunk therein, each of said rungs being split along an axial plane and provided with a central bore, a bolt inserted insaid bore, and means drawing said bolt, rung and sides together, a sleeve adapted to surround'and hold together the two parts of each rung, said sides being provided with grooves along their edges and across their upper ends, a continuous wire embedded'in said grooves and spaced bracing bolts through said sides, a hook formed at one end of each bolt, a nut'threaded on the other end thereof and a hooked washer under saidnut, said hooks engaging with oppositely situated portions of said continuous wire.

In testimony whereof I affix I GEORGE E. WALGi-ILI. [us] my signature. 

